gas grill burns in the wrong place

I've just tried using my gas grill for the first time in a few months, but the flame starts burning down around the venturi, as well as up on the burner where it's supposed to. This has been an occasional problem in the past, but now it's at the point where I don't want to use the grill. Any suggestions on what might be causing the problem?
I've tried adjusting the air/fuel mixture and the length of the venturi tube, but neither makes any difference. The problem seemed to get better when I removed the lava rocks and the grate that holds them, but it didn't go away completely. Besides, it won't grill very well that way.
The grill is an ancient post-mounted Charmglow burning natural gas. The burner and venturi are only a couple of years old.
--
Ray Heindl
(remove the Xs to reply to: snipped-for-privacy@yaxhoo.com)
  Click to see the full signature.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Be sure the venturi tubes are completely clear. Cold be a little spider web in them.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Wasps and mud dobbers are bad about plugging up little spots too. Ún
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

There was a tiny bit of web in the venturi, but clearing that out didn't fix the problem. But I did get motivated to remove the valve/regulator assembly, and there was some web way down inside the valve. I cleaned that out, and it seems to be working now -- 15 minutes of burning without flashback. And it seems to be a lot hotter than it used to be.
I'm wondering if I've got the wrong venturi, though. Even with the air supply all the way open, the flame is really yellow when it's on high. Is that normal? Does natural gas require a different venturi than propane?
On a related note, can anyone recommend a good source of replacement burners? The thin stainless ones don't seem to last very long; does anyone make good cast-iron ones, or heavy-gauge stainless?
Thanks for the help, everyone.
--
Ray Heindl
(remove the Xs to reply to: snipped-for-privacy@yaxhoo.com)
  Click to see the full signature.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
There are different orifices for natural gas and for propane, you need to change them to get it working correctly. Check with whomever made your grill if you converted it from propane to natural gas and didn't change them at the time.
--

Mikey S.
http://www.mike721.com
  Click to see the full signature.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

As far as I know the grill has always been run on natural gas, so I presume the regulator and valve were designed for that. Where is the orifice located -- in the valve/regulator somewhere?
When I've bought replacement burners and venturis I've always specified that it was for natural gas, but the sellers have always assured me it doesn't matter. I wonder if that's true, though. Natural gas would need less air than propane (if my chemistry teachers are to be believed) so maybe that's not the problem.
--
Ray Heindl
(remove the Xs to reply to: snipped-for-privacy@yaxhoo.com)
  Click to see the full signature.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Valves
True. The burner is the same, the orifice takes care of the mix along with the venturi adjustment.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The orifice is at the end of the valve, the little precisely drilled hole that lets the gas into the venturi. Since it's always been on natural gas though I guess that's not the problem..maybe the burners just need a good cleaning, my grill gets nasty every year and burns yellow till the burners get wire brushed and all the little rusty holes in them poked open again.
--

Mikey S.
http://www.mike721.com
  Click to see the full signature.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Mine has nothing that looks like a precisely-drilled hole; the gas comes out of the valve, turns a couple corners, and squirts up into the bottom of the venturi. The only holes involved that look at all precise are in the body of the valve, and they do the high/medium/low selection. Maybe that's why it likes to flash back.

Could be. There seemed to be a lot of rust on the burner, flaking off quite a bit. I tried to knock off as much as I could without wrecking it, but I didn't brush it or poke anything in the holes. I'll give it a shot.
--
Ray Heindl
(remove the Xs to reply to: snipped-for-privacy@yaxhoo.com)
  Click to see the full signature.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/5/2004 5:30 PM US(ET), Ray Heindl took fingers to keys, and typed the following:

that critters build homes in the tubes, be they spiders or wasps. Another problem I had was that my burners are cast iron and the little holes had rusted over to where they clogged the holes. The holes were not that round to begin with. I drilled out every hole using a small drill bit.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
130.133.1.4:

When you shut off your BBQ, turn the tank off first and then the burners after they go out from lack of gas from the tank. This way, the excess gas is not in the line and the spiders won't seek out that spot for their homes. There is something in the gas that attracts them. Home Depot and others sell a flexible brush that will clean out the pipe.
Good luck.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Unfortunately that's not an option for me, as the grill is hooked up to a natural gas line. I'll suggest it to the relatives with tank-gas grills, though.

I've wondered about that. The spiders love to nest in the top of the valve, where the gas comes out. In fact, I just cleaned one out of there yesterday. Maybe they like the smell of the odorant in the gas.
--
Ray Heindl
(remove the Xs to reply to: snipped-for-privacy@yaxhoo.com)
  Click to see the full signature.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.